Radial arm saw



March 3, 1954 w. l.. GASKELL ETAL 3,123,108

RADIAL ARM SAW 7 Sheets-Sheet l Filed Feb. l, 1961 i fax/ww@ March 3,1964 w. L. GASKELL ETAL v 3,123,108

RADIAL ARM SAW Filed Feb. l, 1961 7 Sheets-Sheff(I 2 @swf/sf March 3,1964 w. L.. GASKELL ETAL RADIAL ARM SAW 7 Sheets-Sheet 5 Filed Feb.

March 3, 1964 w. L. GASKELL' ETAL 3,123,108

RADIAL ARM sAw Filed Feb. l, 1961 '7 Sheets-Sheet 4 fri. Ail-A. i n

j@ 5&4' a2- i A @um 40 i4 id.

(g l l .152

Il 274 U 2;

52 'i i "9" I 462 iii fv- 5 J. I J

armi/$1' March 3, 1964 w` ..GAsKEl l ETAL 3,123,108

RADIAL ARM SAW 7 Sheets-Sheet 5 Filed Feb.

INVENTOR', aseZZ 'dres L'yy March 3, 1964 w. GASKELL ETAL 3,123,108

RADIAL. ARM SAW Filed Feb. l, 1961 '7 Sheets-Sheet 6 4524.4 45a /I/ 450*s vx 25 46.2 m 4M f"V` 442 44d 43g @j igll armi/5! March 3, 1964 w. L..GASKELL ETAL 3,123,108

RADIAL ARM sAw Filed Feb. 1, 1961 '7 Sheets-Sheet 7 7M Q l ya@ UnitedStates Patent O 3,123,108 RAJAL ARM SAW altcr L. Gaslteil; Ypsilanti,and harles Seitz, Ann Arcor, Mich., assignors to King-Seeley ThermosQ0., a corporation of Michigan Filed Feb. l, 196i, Ser. No. 86,454 2Claims. (Cl. 143-6) This invention relates generally to woodworkingtools, and more particularly to an improved radial arm saw.

A radial arm saw, in accordance with the present invention, isrelatively accurate, ilexible and is relatively economical tomanufacture. Accuracy, flexibility and manufacturing economy areachieved through a novel orientation of the relatively moving componentsof the saw coupled with the provision for adjustment of the relativelymoving components, both to compensate for the dimensional errorsinherent in any manufacturing process, and, in order to make the radialarm saw more practicable in eld use, to .compensate for Wear of therelatively moving components.

The radial arm saw comprises a base surmounted by a work supportingtable. A vertically oriented column is supported Iby the base andsupports a radial arm at its upper end. A carriage is supported by andmovable longitudinally of the radial arm for the support of a power unitcomprising an electric motor and a tool holding arbor. The power unit ismovable in translation longitudinally of the radial arm to effect, forexample, a cut in the workpiece.

Flexibility of the radial arm saw is maximized by a construction thatprovides for rotation of the vertical column with respect to the worksupporting table thereby to provide for orientation of the arm andcutting blade to any angle drawn in the plane or" the work table. Thearm is elevatable with respect to the column and table to vary the depthof cut effected by the blade and to accommodate Nori-:pieces ot varyingthickness. The depth of `cut is related to the vertical position of thearm with respect to the column and table, to the thickness of theworkpiece, and to the angle of the cutting blade with respect to theplane of the table. The power unit is rotatable with respect to itscarriage about both a horizontal axis and a vertical anis there-by tomaximize the lexibility thereof. The table is slidable in its own planewith respect to the vertical column to maximize the length of atransverse cut possible on the workpiece.

Accordingly, one obiect of the present invention is an improved radialarm saw of the type particularly adapted for the mass market in homewoodworking tools.

Another obiect is a radial arm saw wherein the vertical support columnis rotatable with respect to a saw table.

Another object is a radial arm saw wherein the radial arm is elevatablewith respect to the vertical support column,

Another object is a radial arm saw having a plurality of mutuallycomplementary adjustments to minimize production tolerance limitations.

Another object is a radial arm saw having improved means for lockingtherelatively movable components in a desired position.

Other objects and advantages of the present invention will becomeapparent from the study of the following specification and claimswherein reference is made to the drawings in which:

FlGURE l is a side elevational View of the radial arm saw partiallybro-ken away for clarity;

FIG. 2 is a front elevational view of the radial arm saw taken in thedirection of the arrow 2 of FllGURE l;

FIG. 3 is a rear elevational view of the radial arm saw taken in thedirection of the arrow 3 of EEG. l;

FIG. 4 is a cross sectional View taken substantially along the line 4 4of FIG. 3;

FIG. 5 is a cross sectional view taken substantially along the line 5 5of FlG. 3;

FIG. 6 is a top view of the radial arm saw taken in the direction of thearrow d of FIG. 3;

FIG. 7 is a cross sectional view taken substantially along the line 7 7of FIG. 6;

FIG. 8 is a top view of the radial arm similar to FlG. 6 with the coverthereof removed to show the tool supporting carriage;

PEG. 9 is a side View or" the carriage of FIG. 8, partially broken awayfor clarity;

FIG. l0 is a cross sectional view taken substantially along the linelil-ld of PlG. 8;

FIG. l1 is a cross sectional View along the line 'l-ll of FlG. 9;

FIG. 12. is a cross sectional View along the line l2-r2 of FIG. 10;

FlG. 13 is a top view, partially in section, of the vertical columnwitnthe radial arm removed therefrom;

FlG. 14 is a fragmentary side view of a portion of the power unitshowing the slots for indexing rotation thereof about an axis parallelto the plane of the table;

FlG. 15 is a sectional View of the power unit taken substantially alongthe line .i5-l5 of FIG, 2; and

FIG. 16 is a cross sectional view talren substantially along the line`ltdlo of FIG. 15.

Referring to FlG. l, a radial arm saw Ztl in accordance with the presentinvention comprises a work supporting table 22, a vertically orientedcolumn 24, a radial arm 25, anda carriage 23 movable longitudinally ofthe radial arm 25 for the support of a power unit having a tool 32, forexample, a disc saw, mounted thereon. The column Z4 is supported forrotation with respect to the table 22 to provide for movement of thearrn 2e to any desired angle with respect to the table 2,2. The arm 25is elevatable with respect to the table .22 and column 2d to vary thedepth or cut or" the blade 32 and to accommodate worlrpieces of varyingthickness. The carriage 2S is movable longitudinally of the arm 2d toeil-ect a cut in the workpiece at an angle dictated by the rotationalposition of the arm The depth or cut is dictated by the Verticalposition of the arm 26 with respect to the column Zd and table 22 aswell as to the thickness of the workpiece and to the angle of the blade32 ith respect to the plane of the table 22.

More specically, the radial arm saw Zi? comprises the table Z2preferably made of laminated wood construction, for exarnple plywood,for the support of a workpiece (not shown). The table has an upstandingguide lil that extends laterally across the table near the rearward edgethereof to define an index position for the workpiece with respect tothe angular position of the radial arm 26. It is to be noted that ythetable 122 comprises a front portion taken substantially takensubstantially E i2 and a rear portion 44, the guide 443 being interposedtherebetween. The guide 4d is removable from this intermediate positionand insertable behind the rear portion 44 to facilitate ripping ofrelatively wide workpieces, as will be discussed.

As best seen in FlGURE 2, a pair of generally parallel forwardlyextending table support channels 5t) and 52 are secured to a basecasting 54 by a plurality of machine screws 56. A pair of forwardlyextending rails 60 and o2 surrnount the upper iiange portions tif-i and65 of the channels 5G and 52, respectively, and are spaced therefrom bya plurality of resilient pads 7@ that are interposed between the rahseti-o2 and the flanges o45-66. Complementary bolts 72 extend centrallyof each pad 70 to bias the rails 6l? and 62 toward the channels 5l) and52 respectively thereby to compress the pads 7i?. In this manner therails el? and 62, and therefore the table 22 may be leveled or adjustedyto a desired position with respect to the base 54 simply by tighteningselected ones of the bolts 72, thereby to compress associated ones ofthe pads 7i?.

The rail dit has a downwardly extending flange 80 on the inner edgethereof which is engageable with a forwardly extending guide rail Sd onthe underside of the table 22.

ln this manner, the table 22 is guided for movement parallel to and withrespect to the channels 50 and S2. The rails 6t3-62 have outwardlyextending terminal edges 9@ and 92 that are engaged by a pair ofunderlying lingers 94 and 96 on a pair of table locking brackets 98 anditil?, respectively. A plurality of screws 294 with wing nuts attachedthereto extend downwardly through the front portion of the table 22 andthrough suitable apertures in the lingers 9d and 95 ofthe brackets 98and 1li@ so as to facilitate tightening of the lingers 94 and 96Iagainst the outboard flanges 9i? and 92 on the rails oli and 62,thereby to lock the `table 22 against movement with respect to thechannels 50 and E2. Screws S (HGURE 3) in the front table portion 42hold the fingers 94, 96 in sliding engagement with the anges 9th, 92.

A pair of thumb screws il@ (one of which is shown in FIGURE l) aresecured Ito the rearward end of the rails i12 and iid, thereby to lockthe guide rail 40 between the table sections 42, ed. if desired, theguide -rail 40 can be removed from its position intermediate the frontand rear sections 42 and d4 of the table 22 by simply loosening thethumb screws llt), removing the rail 4t), sliding the rear section ififorwardly, replacing the rail 4t) a-t the rearward edge of the table,and tightening the thumb screws liti. The rails i212, 114 are xed to thefront table portion by screws M5.

As shown in FIGURE l of the drawings, when the carriage 2d is at therearward limit of movement, the vertical center line of the disc saw 32is spaced rearwardly of the guide itl and forwardly of the rear edge ofthe table 22. The aforementioned slideable relationship between thetable 22 and channels 5t) and 52 permits workpieces wider than the fulltravel of the saw to be cut. initially, the carriage 23 is positioned asfar rearward as possible and the workpiece positioned forward of thesaw, just clearing the teeth. A iirst cut is made to the limit offorward travel of the carriage 2S. The saw then is stopped and thecarriage 2S moved to the rear. The cut is completed oy positioning thetable 22 rearwardly as far as possible, with the guide at the rear edgeand the workpiece against the guide. The previously described guide S.insures that the table will remain properly aligned with the saw tocomplete the cut.

Adjustab'dity of the guide of the table is also desirable to facilitateripping of wide workpieces.

As best seen in FEGURE 3, the column support casting 5d has a verticalbore 23% therein for the acceptance of the vertically extending column2d. The column 24 is supported for rotation with respect to the columnsupport casting 54 by an annular ring 132 that is keyed to the column 24as by a pin i3d (FiGURE l). The ring has a lower end face 135 that isengaveable with an annular seat 133 on the base support casting 54 totransfer the load of the column 24tto the base casting 54.

The arm 26 and vertical column 24 are radially indexed to major angleswith respect to the base casting 54 by an index pin 14o (FIGURE 3) thatdrops into `one of a plurality of rectangular index slots (FIGURE 13)142, it-4 and 346 in the annular ring 132. rlhe index pin 140 isslideably supported in a transverse bore in the base casting Sii and hasa rectangular inner end portion 152 for engagement in one of the slots142, 144i and 146 in the annular ring 232, a spring 154tnormally biasingthe index pin lei? radially inwardly toward the annular ring 132. Ahandle 156 facilitates pulling of the pin outwardly to index the column.A suitable set screw 153 engages a complementary flat 166 on the indexpin 146 to preclude rotation of the pin in the bore l5@ in the basecasting S4.

Referring to FIG. 4, the column 24 is lockable against rotation withrespect to the base casting `54 by a barrel lock lil. The barrel lock189 comprises a head portion 182 that is supported within a bore 3.33 inthe base casting S4; for movement axially thereof. The head portion 182has a tapered cam face 184 engageable with the column 24 and a centralbore M6 with a conical seat 188 therein for the acceptance of the headportion 19t) of a locking screw 72.

rl`he locking screw 192 extends generally tangentially to the verticalcolumn 24 and is threadably engaged with a complementary nut 294 toeffect tightening of the barrel lock 1181i. A cam member 196 isinterposed between the head portion iii-2 and the nut 194 and has a caniface 198 engageable with the column 24. A suitable handle 2li() having aknob 262 (FIGS. 1 and 3) at the outer end thereof is secured to the nut194i to facilitate rotation thereof. A spring 2l@ is interposed betweenthe head and cam members M52 and i915 of the barrel lock 180 to normallybias these components apart to facilitate rotation of the column 24 withrespect to the base casting 54. It is to be noted that the tighteningscrew 3.92 is adjustable to an initial position as by rotating the screw192 with respect to the nut 194 which is accomplished by inserting ascrewdriver in the head portion 196 of the screw 192. A suitable plug isadvanceable axially of a counterbore in the head 182 to lock the screwi92 in the initial position. After an initial bias of the head 182 andcam member 196 on the column 24tis obtained, tightening `of the barrellock 12) is effected by rotating the handle 20d through a relativelysmall arc thereby to restrict rotation of the column 24. -In thismanner, the barrel lock is relatively easily adjustable to preclude thecondition obtaining wherein a large increment of rotation is required ofthe handle 294) to effect locking of the barrel lock 180 against thecolumn 24.

As best seen in FIG. 13, an index plate 220 having appropriate indicia222 on the upper surface thereof is secured to the upper face of theannular ring 32 as by a plurality of drive pins 224. The index plate 22dhas a downwardly turned outer peripheral edge 226 (FIG. 1) for theretention of a seal 22g between the upper edge face of the base castingS4 and the index plate 226, thereby to preclude the inltration offoreign material into the base assembly. A pointer 23? (PEG. 3) issecured to the base casting S4 to cooperate with Vthe indicia 222,giving a visual indication of the rotative position of the column 24 andradial arm 26 with respect to the base casting 5d.

As best seen in FIG. l, a downwardly extending screw 255i? is threadablyengaged in a transversely extending nut 252 in an upper end portion 254of the column 24. The nut 252 is secured to the upper end portion 254 ofthe column 24 as by a pair of pins 256 and 25S and is movably axially ofthe pins 256 and 25S to facilitate selfalignment with respect to thecolumn 24:.

An upper end portion 26d of the screw 25d is journaled in acomplementary bore 262 in a head casting 270. lA handle 272 is securedto the upper end portion 260 of the screw as by a nut 274, relativerotation therebetween being restricted by a transverse pin 276. The pinextends radially outwardly through a vertically orientated slot 278 inthe handle 272 to provide for tightening of the handle 272 downwardlyagainst the head casting 27S) to accommodate wear therebetween. Asuitable hand knob 28d is secured to an outer end portion 232 of thehandle 272 as by a screw and nut 2t4.

Elevation of the head casting 27d with respect to the column 24 iseffected by rotation of the handle 272 with respect to the head casting279, the screw 25d upon rotation moving axially of the nut 252 whichmovement is transmitted to the head casting 276 by a thrust bearing 236at the upper end of the screw 25d. The head casting 270 is provided witha pair of annular bearing flanges 2% and 292 that engage the verticalcolurne 24 slideable relation to guide the head casting 27@ for verticalmovement.

As best seen in FlGURE 5, relative rotation between the head casting 27?and the vertical column 24 is prevented and frictional locking iseffected by a key 3th) that is slideable longitudinally of the verticalcolumn 24 in a complementary key-way 362. The key 3% is resilientlysupported with respect to the Vertical column 24 by a spring member 394that is fixedly secured to the head casting by nuts and bolts 31%. The1ey 3d@ is biased into the key-Way 392 to lool: the head 276 againstmovement vertically with respect to the column 24 by a locking screw310. The locking screw 3l() is threadably engaged in an internally andexternally threaded bushing 3l2 that is accepted in a complementarythreaded bore 3114 in the head casting 27d. The bushing 312 is lockedagainst axial movement with respect to the head casting 27S by a locknut The bushing 332 is first advanced with respect to the head casting27@ to position the inner end portion of the bushing in loose engagementwith the ltey Still. The lock nut Slo is then tightened, whereupontightening or backing off of the locking screw Slt), as by rotation of ahandle 32@ (FIGURE 3), effects relative aidal movement of the lockingscrew Slt? with respect to the bushing 312 and lrey 300. In this manner,tightening of the locking screw Eli? will lock the key 3d@ in thekey-way 392, thereby to hold the head casting in any selected verticallocation. Upon loosening of the screw 31d, the head casting can beraised or lowered, but the bushing will hold the key in slidingengagement with the key-way to prevent rotation of the casting withrespect to the column 249. Thus, it will be seen that this constructionaffords both a simple means to lock and unlock the head casting 276 withrespect to axial movement on the column 243, and also insures againstrelative rotation between the head casting 27@ and the column 249.

As best seen in FlGURES l and 3, the head casting 27d has a pair ofspaced parallel horizontal bores 346;? and 342 therein. A pair ofhorizontally extending tubular shafts and 346, respectively, are held inthese bores by set screws (not shown). The shaft 344 is relativelylarger than the shaft 34d and provides the principal support for thecarriage 28. The shaft 34o is used both to aid in supporting thecarriage 255 and to restrict rotation of the carriage 2d about the mainshaft 344. An end casting 35i) (FIGURE 1) having a pair of aperturescomplementary to the shafts 344 and 345, ties the outer ends thereoftoget -er and is secured to the shafts 344 and 346 as by suitable pins351. A suitable trim member or cover overlies the shafts and to shieldthe shafts 344 and 346 and the carriage 2S against the infiltration ofdust and foreign materials.

As best seen in FIGURE 9, the carriage 2S comprises an upper section anda lower section 4&2, which may be, for example, die castings. Thecarriage sections 4% and 4&2 have suitable arcuate sections 4524 and43d, (FEGURE l0) respectively, `for the acceptance of the shaft 346 andarcuate sections 4% and 4rd (FIG- URE 1l), respectively for theacceptance of the shaft 344. The sections 400 and 462 are securedtogether by a plurality of machine screws 4t2, 4l4, 4to and 4&3 thatextend downwardly through suitable apertures in the upper section 4% andare threadably engageable in complementary threaded bores in the lowersection 462.

lt is to be noted the upper section 460 is provided with a pair offulcrums 42%, (one of which is shown in FIG- URE 9), on opposite sidesof the shaft 344, that function as pivot points when the sections 4d@and 462 are joined together by the screws 4M, 418. The fulcrurns 429, inconjunction with a pair of set screws 422 and 424 that are threadablyengaged in the upper carriage section ll in parallel relationship to andadjacent the machine screws 4G12 and 414, facilitate alignment of thesections 4d@ and 462. Adjustment of the sections 4h19 and 462 isaccomplished by advancing or retracting the set screws 422 and 424 tobias the carriage section 492 about the fulcrums 42%) with respect tothe section 49d, the machine screws 412 and 414 being tightened aftersuch adjustment is effected to positively retain the carriage sections490 and 4ll2 in a desired alignment. This adjustment is provided tobring the lower section 4t2 into parallel with the longitudinal axes ofthe shafts 344 and 34o.

Referring to FIGURE ll, the upper section 4d@ of the carriage 23 issupported for movement with respect to the support shaft 344 by a pairof circumferentially spaced rollers 439 and 432. The rollers 43d and 432are ball bearing supported on a pair of shafts 434 and 43H5,respectively, that are oriented in generally tangential relationship tothe shaft 344. rThe pins 434 and 435 are supported in a pair ofcomplementary recesses 449 and 442 in the top section 4G@ of thecarriage 2S. It is to be noted that the carriage 2S has a second set ofrollers (not shown) similar to the rollers 43d and 432 at the rear endof the upper section 49d, the orientation and function thereof beingidentical to the rollers 43d and 432 thereby to positively support thecarriage 28 for movement longitudinally of the main support shaft 344.

Rotation of the carriage 23 about the central axis of the shaft isprecluded by a roller 46h (FIGURE l2) supported on a roller pin 462 thatis accommodated in a complementary recess 464 in the top section 46? ofthe carriage lt is to be noted that the roller 46S engages the shaft 346and, because of its radial spacing from the center line of the shaft344, precludes rotation of the carriage 2d about the central axis of theshaft The rotational position of the carriage 28 about the line of theshaft is adjusted by advancement cr retraction of a pair of set screws4de and 46S (FIG- il t at a e provided with suitable lock nuts 47? and472, res ectively, thereby to dene he vertical position of .he pin ofthe roller 45d. Advancement or retraction of the set screws and 463lowers or raises the pin 2 in its complementary slot in the uppersection of the carriage 2S thereby rotating the upper se tion about thecenter line of the shaft 344 to provide for alignment of the lowersection 4422 With the plane cont i g the lowermost surfaces of theshafts. lower se tion of the carriage 2S is, of course, coin, entary tothe upper section 4%@ and is provided with a number of rollers topositively locate the carriage 2S on the shafts and 346 thereby tolir-iit the carriage reciprocating movement with respect to the shaftstand 346.

As best seen in FGURES 9 and ll, the lower section of the carriage 23has a roller Still underlying the slait and supported on a tangentiallyoriented pin The pin db2 is movable vertically of the carriage l-l2 in avertically oriented recess 5% (FIGURE 9) and is biased verticallythereof by a pair of set screws 5538 and The set screws 5% and 569 areprovided with suitable lool: nuts 512 and 5l4, respectively, so that,

upon advancement of the set screws 528 and Sir), the roller Sil@ isbiased vertically against the shaft As best seen in FIGURE 9, a roller516 similar to the roller Stal) is mounted on a pin 513 that is disposedin a vertical slot 52d in the carriage section 4:92. The pin 518 ismovable vertically of the slot 52@ under the bias of a pair of setscrews 522 (one of which is shown), suitable lock nuts 524 beingprovided therefore to lock the pin 518 at a desired vertical level. Inthis manner, the carriage 23 is positively positioned on its supportingshaft 344.

As best seen in FIGURE l2, the bottom section db2 has a roller 5.3i)underlaying the shaft 346 at a point directly beneath the roller dei?,whereby the roller dei? can be biased downwardly against the shaft 346after vertical adjustment thereof. The roller 53@ is supported on a pin532 that is movable in a vertically oriented slot 531i under the bias ofa pair of adjustment screws 536, (one of which is shown), which arelocked by suitable lock nuts 538.

A friction drag is provided for adjusting the freedom of carriagemovement. This comprises a plug 53S of durable, low-friction material,such as Teflon, located in a vertical bore 537 and biased against theshaft 346 by a set screw 539 acting through a resilient spacer plug S41of rubber or the like.

Referring to FIGURE 9, the carriage 23 is lockable longitudinally of theshafts Seid and 346 by a locking collar 54h. The collar 5d@ is disposedabout the shaft 344 and is tightened thereagainst upon advancement of ascrew 542 having a handle 54.14 thereon to facilitate hand tighteningthereof. The collar 540 is restrained from movement with respect to thecarriage 28 by a set screw 56 (FlG. l0) that is engaged in acomplementary V-groove 54S in the collar 54h. A seal 549 may be providedbetween the collar 5449 and sections itil? and dil?. to preclude thepassage of foreign materials into the carriage 28.

As best seen in FIGURE 7, the lower section 492 of the carriage 28 isprovided with a generally circular downwardly facing boss 551B having acentral aperture 552 for the acceptance of a vertically extending pin560. The pin 56@ extends upwardly through a central aperture 562 in agenerally circular top plate 565i of a downwardly depending power unitsupport arm 57). The arm 57i? is rotatable with respect to the carriage2S about the pin 56d. The arm 57d is lockable at a desired rotationalposition with respect to the carriage 2S upon tightening of a nut 53)that is disposed about the upper end of the pin 560. The nut 5S@ has aradially outwardly extending arm 552 with a handle 58d thereon (FIGURE6), rotation of the arm dZ and nut Sdi) effecting tightening of theconnection between the arm 57@ and boss 550 of the carriage A pluralityof dished or spring washers S86 maintain a slight tension across theconnection to eliminate play between the parts when the nut 5815 isloosened.

Because it is desirable to effect tightening of the nut S80 upon apredetermined maximum arcuate movement of the arm 582, provision is madefor the presetting of the rotative position of the nut 53d with respectto the pin 561B.

As best seen in FIGURE 7, a locking plate 591i is disposed about the pin5613 and keyed thereto as by engagement of a pair of diametricallyspaced flats S92 on the pin 5d@ (one of which is shown) with acomplementary aperture in the plate 5?15. The plate 59@ has a pluralityof radially inwardly extending circumferentially spaced slots 59d forthe acceptance of the inner end portion of an index screw 5%. Uponbacking off of the index screw Sile, the plate 526 is rotatable with thepin 56@ which is rotated as by engaging a conventional socket wrenchwith a hexagonal head portion thereof.

Adjustment of the connection between the carriage 2S and the arm 57S isinitiated by placing the handle 532 and nut Stili at a desired loci-:edposition whereupon the pin S60 is advanced until a desired lockingtension is obtained across connection. The screw 5% is then advancedradially inwardly until the inner end portion thereof engages in one ofthe slots 594 in the plate 599 thus precluding further rotation of thepin 561) with respect to the carriage 2d. Thereafter, rotation of thenut handle 532 edects a backing off of the nut with respect to the pinSe@ freeing the arm 57@ for rotation with respect to the carriage 2S. lnthis manner a positive locking between the arm 579 and carriage 28 isobtained by a relatively small increment of rotation of the lockinghandle 582, the lock position of the handle S32 and therefore therelease position thereof being positively predetermined but readilyreadjustable if necessary or desirable.

As best seen in FEGURE 6, rotation of the arm 570 with respect to thebottom section 40?; of the carriage 28 is indexed by a verticallyextending pin eil@ that is supported for vertical movement by ahorizontally extending pin 602 having a handle 664 at an outer endthereof. The pin 6d?. is movable vertically of the lower section M52 ofthe carriage 28 in a vertically oriented slot 666 (FGURES l and 2), thevertically oriented pin 6d@ moving into engagement with selected ones ofa plurality of conical head set screws 61d, 616 on the arm 57h. The setscrews 61d, 616 have conical head portions so that, upon retraction oradvancement thereof with respect to the upper end portion 5de of the arm57? the rotational position of the arm 57@ with respect to the carriage28 can be adjusted. ln this manner the plane of the saw blade 32 isaligned with the longitudinal axes of the supporting shafts 344 and 346in an index position. It is to be noted that the pins 61d and 616 areangularly related to one another with respect to the central axis of thepin 569 so as to lock the arm 57d and therefore the blade 32 in eitherthe crosscut position parallel to the shafts 34rd and 346 or in a planenormal to the central axis of the shafts 344 and 346 to facilitateripping of a workpiece.

As best seen in FIGURES l5 and 16, the power unit 3h comprises a housing701il for the support of a high speed electric motor. The housing 76dcomprises an annular front section 762, an annular intermediate section7 54 and a closed cylindrical rear section '796. The front sect-ion 702supports a suitable bearing 711i for the support of the motor armatureshaft 712. The rear section 796 of the housing 7G@ supports a bearing714 for the support of a rear end '716 of the armature shaft 7112. Aconventional wound armature 717 `is mounted on the shaft 712, suitablefield poles 718 and energizing coils therefor (not shown) beingsupported and housed within the rear end section 766 of the housing.

A fan 729 is mounted on the armature shaft 712 intermediate the bearing71e and the armature 717 for the purpose of inducing a flow of airaxially inwardly through the end wall of the rear housing section 766,and thence through the motor housing 70th The front end portion 702 ofthe motor housing 7% encloses and supports a tool supporting arbor 75@having a worm gear 752 mounted thereon in operative association with aworm 754 mounted on an outer end 756 of the armature shaft 712. A safetyclutch comprising, for example, a plurality of Belleville washers '759,transmits rotation of the `armature shaft 712 to the worm 754 therebyeffecting rotation of the worm gear 752 and tool supporting arbor 750.

It is to be noted that the front end portion 7&2 of the housing 7d@ isclosed by an end plate 76d that is secured, as by a screw 764, to aradially extending plate 762 on the housing portion 7%2. The plate 762closes the worm and worm gear compartment.

In accordance with one feature of the present invention, the end plate76d has a plurality of radially outwardly Y opening apertures 766 in anaxially extending flange 768 thereof to direct the flow of air inducedthrough the motor housing 7 il@ by the fan 720 radially outwardly of thehousing Idil and against the workpiece in the area of contact of the sawblade 32 therewith to blow sawdust away from the immediate area of theout in the workpiece. In this manner, the llow of air through the motorhousing 74H) serves a dual function, namely, cooling of the motor andthe clearing of vsawdust away from the area of the cut in the workpiece.

A handle 7&4) is secured to the end portion 7% of the housing 7% tofacilitate pulling of the power unit 3d and carriage 23 longitudinallyof the radial arm 26. The handle 789 encloses a switch 782 that isactuated by a pivotally supported trigger 784. A flexible electricalconductor 736 extends into the motor housing 70d and handle 78@ toeffect energization of the motor through the switch 732.

The motor housing 760 is supported with respect to the downwardlydepending arm 57d in an annular ring Sill? complementary to theintermediate portion 764 of the housing 7th?. The inner portion 704 ofthe housing 790 serves as a bearing surface to facilitate rotation andindexing of the housing 70d with respect to the ring 800 of the arm57i?.

As best seen in FIG. 16, the motor housing 70d is locked againstrotation with respect to the ring 80u of the arm 72= by a barrel lock894 comprising a tubular member S66 having a cam face 80S thereonengageable with the intermediate portion 704 of the housing 769. Thebarrel lock 894 has a shaft S19 that extends through the tubular member865 and is engageable with a member 812 at the opposite end thereof. Themember 812 has a cam face 14 engageable with the intermediate portion79e of the housing 76d. The shaft 316 has a rectangular head portion 315that is accepted in a complementary recess 813 in the member 812 therebyto preclude relative rotation therebetween. Movement of the members 865and 812 toward one another is effected by tightening a hand knob S2@against the tubular member 806 thereby to bias the cam faces 3tlg andSie of the members 866 and 812, respectivelyV against the intermediatemember 7% of the housing 7%. The members 8&6 and 812 are normally biasedapart by a helical compression spring 22 that extends extends betweenthe cam members 3% and 312 and is normally accepted within a peripheralgroove 824 in the intermediate member 704;- (FIG. 14).

The motor housing 7Go and therefore the arbor shaft 75o can bepositioned and locked at any desired rotational position with respect tothe vertically extending arm 5721i. However, when it is desired to indexthe motor housing 70) and therefore the plane of the saw blade 32 in,for example, a vertical plane, an index pin 9d@ is engageable in one ofa plurality of complementary slots 9d?. in the intermediate portion 704of the housing 76d, (FGS. 14 and l5). The index pin 96% is normallybiased downwardly by a helical compression spring 93e and is movableupwardly upon vertical movement of a transversely extending pin 996having a handle 9%. The pin 9de is movable in a vertically extendingslot 914i. An index plate 92d (FIGS. 2 and 15) having suitable indiciathereon to indicate the angle of rotation between the motor housing 79%and arm 57d, cooperates with a pointer 922 that is secured to the arm570 by a machine screw 924.

Thus, the power unit 3d can be rotated to any desired rotationalposition with respect to the arm 57d` and locked therein by tighteningof the barrel lock 8d4 by rotation of the knob 82d thereof. To indexrotation of the power unit 3% to the most used positions, for example,the position wherein the blade 32 is in a vertical plane with respect tothe work table 22 or at angles of 9G degrees on either side of avertical plane, the index pin 9b@ is engageable in the slots 962 in theintermediate portion 704 of the housing 7139.

As best seen in FIGURES 1 and 3, a saw blade guard itl 16W is secured tothe power unit 3i? so as to be movable therewith. The guard lillldsupports a downwardly extending dog shaft 1062 that is verticallypositionable with respect to a workpiece (not shown) so that a rotatabledog 1063 thereon will engage the workpiece to preclude kickback duringripping operations. ln this connection, it may be noted that rip cutsnormally will be made with the carriage 23 locked in place and the powerunit 30 set with the blade 32 parallel to the guide 4t). The workpiecethen is moved beneath the stationary power unit, with the dog 1603 beingtilted rearwardly on the workpiece to prevent reversal of the directionof workpiece movement.

The dog shaft 1002 is lockable in any desired vertical position uponrotation of a knob lltle.

In accordance with another feature of the present invention, a workpiecehold-down arm will is slideably supported by a pin 1t`i'22'that extendsthrough a suitable aperture in the frontal edge 1%24 of the guard i666.The pin w22 extends through a suitable slot M126 in the holddown arm1629, to guide and support the arm 102i) for movement with respect tothe guard, the curvature of the arm w20 being complementary to thecurvature of the frontal edge 102@ of the guard. The pin 1922 has athreaded outer end portion for acceptance within a complementary handknob 163@ whereby, upon tightening of the knob M36, the hold-down arm102) is biased against the frontal edge section 1024 of the cover i?.

The hold-down 102@ has a reentrantly folded lower end portion ldd forengagement with the upper surface of a workpiece (not shown) thereby tohold the workpiece downwardly against the upper surface of the table 22.It is to be noted that in this manner, the hold-down arm is maintainedin ycontinuing engagement with the workpiece, the end portion 1034thereof being slideable across the workpiece upon movement of the blade32 longitudinally of the radial arm 2d. Hold-down 162@ is used only formaking rip cuts.

lt is to be understood that the specific construction of the improvedradial arm saw herein disclosed and described is presented for thepurpose of explanation and illustration and is not intended to indicatelimits of the invention, the scope of which is deiined by the followingclaims.

What is claimed is:

1. In a radial arm saw comprising a base, a table for the support of aworkpiece, a vertical column supported by said base, a radial armsupported by said column and movable vertically thereof, a carriagesupported by said radial arm and movable longitudinally thereof, and apower unit including a tool holding arbor supported by said carriage formovement longitudinally of said radial arm, the improvement comprisingmeans for locking the radial arm vertically of the column by apredeterminable movement of a handle comprising a longitudinal groove onthe outer periphery of the column, a key mova'oly supported in alignmentwith said groove, and means for adjustably biasing said key into saidgroove comprising a threaded locking screw having an end portionengageable with said key and a handle portion, a bushing having internalthreads complementary to said locking screw and external threads foracceptance in a complementary bore in the radial arm, and means on saidbushing for advancing said bushing axially and locking said bushingagainst said key whereby to hold said key in sliding position in saidgroove, said screw being rotatable to advance the end portion to aposition locking said key in said groove.

2. In a radial arm saw comprising a base, a generally planar table onsaid base for the support of a workpiece, a vertical column supported bysaid base, a radial arm supported by said column, and a carriagesupported by said radial arm and movable longitudinally thereof, theimprovement comprising a power unit having a generally cylindricalhousing, an arm depending downwardly from said carriage having acontractible ring Vengageable about the housing of said power unit, saidpower unit having an armature at one end rotatable about the centralaxis thereof and a tool holding arbor at the other end thereof rotatableabout an axis generally normal to the axis of the armature, said powerunit being rotatable about its central ais Within the contractiole ringon said arm to Vary the angular relationship between the central aAis ofsaid tool holding arbor and the plane of said table, the ring on saidcarriage arm encircling said housing between the armature and the arborof said power unit.

Referenees Citerl in the le of this patent UNITED STATES PATENTS 12Wappat Apr. 5, 1927 Hedgpeth Feb. 23, 1932 Hughes July 5, 1932 FlaniganAug. 23, 1932 Clements July 18, 1933 Clarke Oct. 31, 1933 Pearson Aug.26, 1941 Wallace et al Apr. 27, 1943 Gardner Sept. 14, 1943 Schutz July4, 1944 Langfelder May 28, 1946 Johnson Sept. 19, 1950 Johnson Feb. 10,1953 Snyder Nov. 8, 1955 Peterson Sept. 3, 1957 Dooley Nov. 5, 1957Gardner May 20, 1958 Cravens Jan. 27, 1959

2. IN A RADIAL ARM SAW COMPRISING A BASE, A GENERALLY PLANAR TABLE ONSAID BASE FOR THE SUPPORT OF A WORKPIECE, A VERTICAL COLUMN SUPPORTED BYSAID BASE, A RADIAL ARM SUPPORTED BY SAID COLUMN, AND A CARRIAGESUPPORTED BY SAID RADIAL ARM AND MOVABLE LONGITUDINALLY THEREOF, THEIMPROVEMENT COMPRISING A POWER UNIT HAVING A GENERALLY CYLINDRICALHOUSING, AN ARM DEPENDING DOWNWARDLY FROM SAID CARRIAGE HAVING ACONTRACTIBLE RING ENGAGEABLE ABOUT THE HOUSING OF SAID POWER UNIT SAIDPOWER UNIT HAVING AN ARMATURE AT ONE END ROTATABLE ABOUT THE CENTRALAXIS THEREOF AND A TOOL HOLDING ARBOR AT THE OTHER END THEREOF ROTATABLEABOUT AN AXIS GENERALLY NORMAL TO THE AXIS OF THE ARMATURE, SAID POWERUNIT BEING ROTATABLE ABOUT ITS CENTRAL AXIS WITHIN THE CONTRACTIBLE RINGON SAID ARM TO VARY THE ANGULAR RELATIONSHIP BETWEEN THE CENTRAL AXIS OFSAID TOOL HOLDING ARBOR AND THE PLANE OF SAID TABLE, THE RING ON SAIDCARRIAGE ARM ENCIRCLING SAID HOUSING BETWEEN THE ARMATURE AND THE ARBOROF SAID POWER UNIT.